* {
    margin: 0;
    padding: 0;
    list-style: none;
}

.box {
    margin: 0 auto;
    width: 500px;
    height: 200px;
}

.box>.img_box {
    position: relative;
    overflow: hidden;
}

.box>.img_box>ul {
    white-space: nowrap;
    font-size: 0;
    /* transition: 0.2s ease-in-out; */
}

.box>.img_box>ul>li {
    display: inline-block;
    width: 500px;
}

.box>.img_box>ul>li>a>img {
    width: 100%;
}

.box>.img_box>.arrow_left,
.box>.img_box>.arrow_right {
    width: 30px;
    height: 50px;
    text-align: center;
    line-height: 50px;
    font-size: 20px;
    background-color: rgba(0, 0, 0, 0.2);
    transition: 0.3s linear;
    cursor: pointer;
    color: aliceblue;
}

.box>.img_box>.arrow_left:hover,
.box>.img_box>.arrow_right:hover {
    background-color: rgba(0, 0, 0, 0.8);
    width: 35px;
}

.box>.img_box>.arrow_left {
    position: absolute;
    top: 30%;
    left: 0;
}

.box>.img_box>.arrow_right {
    position: absolute;
    top: 30%;
    right: 0;
}

.box>.dot_box {
    text-align: center;
}

.box>.dot_box>span {
    display: inline-block;
    width: 20px;
    height: 5px;
    background-color: gray;
    margin: 0 3px;
    cursor: pointer;
}

.box>.dot_box>.dotActive {
    background-color: #f00;
}

.box>.dot_box>span:hover {
    background-color: #f00;
}